Browan TBMS100 PIR parameter settings

I’m using the TBMS100 at a sunny spot and get many false alerts, to the point of the device being completely unusable. Thus I’d like to adjust some PIR parameters.

There is some basic info availbale on page 13 of the manual:

However, I would like to see a better explanation of these parameters before I start adjusting them.
Has anybody better info on the TBMS100 PIR parameter settings?